Lens barrel

ABSTRACT

A lens barrel is provided that includes a zoom optical system, a zooming unit, and a light adjusting mechanism. The zoom optical system is configured to form an optical image of a subject and includes a first, a second, and a third lens group. The third lens group is movable and configured to move the optical image. The zooming unit causes the zoom optical system to perform a zooming operation. The light adjusting mechanism is configured to adjust the light passing through the zoom optical system. The lens barrel is configured to change between an imaging state and a retracted state. In the imaging state, the zooming operation is performed, and the first, the second, and the third lens groups are in alignment. During the zooming operation, the second lens group moves integrally with the third lens group along the optical axis, and the light adjusting mechanism and the second lens group move independently of one another along the same axial direction. In the retracted state, the second lens group is disposed off center from the first lens group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2010-207501, filed on Sep. 16, 2010 and Japanese Patent Application No.2011-171267, filed on Aug. 4, 2011. The entire disclosure of JapanesePatent Application No. 2010-207501 and Japanese Patent Application No.2011-171267 are hereby incorporated herein by reference.

BACKGROUND

1. Technical Field

The technology disclosed herein relates to a lens barrel. Morespecifically, the technology disclosed herein relates to a lens barrelused in a digital camera or the like.

2. Background Information

Recent years have witnessed the growing popularity of digital camerasthat make use of imaging element such as a Charge Coupled Device (CCD),Complementary Metal Oxide Semiconductor (CMOS) sensor, and the like andconvert an optical image into an electrical signal, and digitize andrecord the electrical signal.

With such a digital camera, not only is a higher pixel count needed forthe CCD or CMOS sensor, but higher performance is needed for the lensbarrel that forms an optical image on the imaging element. Morespecifically, there is a need for a high-performance lens barrel withwhich a higher-magnification zoom lens system can be installed and imageblurring during imaging can be corrected. Furthermore, there is a needfor a lens barrel which can take higher-quality moving images. Forexample, there is a need for a lens barrel with which quiet,extended-time imaging is possible, that is, a lens barrel that hasquietness and also has low power consumption.

Meanwhile, there is a need to reduce the overall size of the product tomake it more easily portable. The lens barrel is considered tocontribute greatly to reducing the overall size of the product, sovarious proposals have been made for making a lens barrel more compact.

With the lens barrel discussed in Japanese Patent Application2008-46504, blur correction is accomplished by moving the imagingelement unit with the actuator in a direction perpendicular to theoptical axis. This type of blur correction is called a sensor shiftmethod.

However, when a sensor shift type of blur correction is used, there isthe risk that the actuator will get bigger than the actuator of anoptical system that performs blur correction by moving a correctinglens. For example, the imaging element weighs approximately three timesas much as a correcting lens. Also, the imaging element requiresnumerous signal lines, so these signal lines must bend while the elementis driven. In particular, digital cameras that make use of CMOS imagesensors to improve sequential imaging performance have become morepopular in recent years. The number of circuit wires connected to a CMOSimage sensor is greater than that with a CCD image sensor, so the driveload ends up being higher. For example, when an imaging element isdriven, at least about five times the energy is required than when acorrecting lens is driven.

As discussed above, with sensor shift blur correction, the actuator endsup being bulkier. Accordingly, it is known that there is a limit to howcompact a lens barrel can be made with sensor shift blur correction.

SUMMARY

A lens barrel is provided that includes a zoom optical system, a zoomingunit, and a light adjusting mechanism. The zoom optical system isconfigured to form an optical image of a subject and includes a first, asecond, and a third lens group. The third lens group is movable in adirection perpendicular to the optical axis and configured to move theoptical image in the same direction. The zooming unit is operativelycoupled to the zoom optical system to cause the zoom optical system toperform a zooming operation. The light adjusting mechanism is disposedbetween the first lens group and the second lens group and configured toadjust the light passing through the zoom optical system. The lensbarrel is configured to change between an imaging state and a retractedstate. In the imaging state, the zooming operation is performed, and thefirst, the second, and the third lens groups are in alignment along theoptical axis. During the zooming operation, the second lens group movesintegrally with the third lens group along the optical axis, and thelight adjusting mechanism and the second lens group move independentlyof one another along the same axial direction. In the retracted state,the second lens group is perpendicularly disposed off center from thefirst lens group.

These and other features, aspects and advantages of the technologydisclosed herein will become apparent to those skilled in the art fromthe following detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred and example embodiments of thepresent invention.

BRIEF DESCRIPTION OF DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a simplified oblique view of a digital camera;

FIG. 2 is a simplified oblique view of a digital camera;

FIG. 3A is a simplified oblique view of a lens barrel (retractedposition)

FIG. 3B is a simplified oblique view of a lens barrel (wide angleposition);

FIG. 4 is an exploded oblique view of a lens barrel;

FIG. 5 is an exploded oblique view of a lens barrel;

FIG. 6 is an exploded oblique view of a lens barrel;

FIG. 7 is an exploded oblique view of a lens barrel;

FIG. 8 is a simplified cross section of a lens barrel (retractedposition);

FIG. 9 is a simplified cross section of a lens barrel (wide angle end);

FIG. 10 is a simplified cross section of a lens barrel (telephoto end);

FIG. 11 is an oblique view of a retractable lens frame and a rectilinearframe;

FIG. 12A is a plan view of a third lens group (retracted state);

FIG. 12B is a plan view of a third lens group (imaging state);

FIG. 13 is an exploded oblique view of the third lens group; and

FIG. 14 is a plan view of an aperture unit.

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting thepresent technology as defined by the appended claims and theirequivalents.

First Embodiment

An embodiment of the present technology will now be described in detailthrough reference to the drawings.

1: Summary of Digital Camera

A digital camera 1 will be described through reference to FIGS. 1 and 2.FIGS. 1 and 2 are simplified oblique views of the digital camera 1. FIG.1 shows when a lens barrel 3 is in an imaging state (wide angle end).

The term “wide angle end” here corresponds to a state in which the focaldistance of an optical system O (discussed below) is the shortest one (astate in which the image angle is the maximum one), and “telephoto end”corresponds to a state in which the focal distance of the optical systemO is the longest one (a state in which the image angle is the minimumone). The state when the power is ON is defined as the imaging state.The state in which the length of the lens barrel 3 is the shortest onewhen the power is OFF is defined as a retracted state. The orientationof the lens barrel 3 in the imaging state is defined as an “imagingpossible orientation,” while the orientation of the lens barrel 3 in theretracted state is defined as a “retracted orientation.”

The digital camera 1 is a device for acquiring an image of a subject. Amultistage telescoping lens barrel 3 is mounted to the digital camera 1for higher magnification and size reduction.

In the following description, the six sides of the digital camera 1 aredefined as follows. The side facing the subject when an image is beingcaptured with the digital camera 1 is called the front face, and theface on the opposite side is called the rear face. When an image iscaptured such that up and down in the vertical direction of the subjectcoincide with up and down in the short-side direction of the rectangularimage being captured by the digital camera 1 (the aspect ratio (theratio of long to short sides) is generally 3:2, 4:3, 16:9, etc.), theside facing upward in the vertical direction is called the top face, andthe opposite side is called the bottom face. Further, when an image iscaptured such that up and down in the vertical direction of the subjectcoincide with up and down in the short-side direction of the rectangularimage being captured with the digital camera 1, the side that is on theleft when viewed from the subject side is called the left face, and theopposite side is called the right face. The above definitions are notintended to limit the usage orientation of the digital camera 1.

The same definitions apply not only to the six sides of the digitalcamera 1, but also to the various constituent members disposed in and onthe digital camera 1. Specifically, the above definitions of the sixsides apply to the various constituent members in the state in whichthey have been disposed in or on the digital camera 1.

As shown in FIG. 1, a three-dimensional perpendicular coordinate systemis defined, having a Y axis parallel to the optical axis A of theoptical system O (discussed below). Based on this definition, thedirection facing the front face side from the rear face side along theoptical axis A is called the positive side in the Y axis direction. Thedirection facing the left face side from the right face side andperpendicular to the optical axis A is called the positive side in the Xaxis direction. Further, the direction facing the top face side from thebottom face side and perpendicular to the X and Y axes is called thepositive side in the Z axis direction.

2: Overall Configuration of Digital Camera

As shown in FIGS. 1 and 2, the digital camera 1 mainly comprises a shell2 that houses various units, the optical system O that forms an opticalimage of a subject, and the lens barrel 3 that movably supports theimaging optical system O.

The optical system O is made up of a plurality of lens groups, and theselens groups are disposed in a state of being aligned in the Y axisdirection. The lens barrel 3 is a multistage telescoping lens barrel.Specifically, the lens barrel 3 is supported by the shell 2. The lensbarrel 3 is a three-stage telescoping lens barrel. This lens barrel 3 isconfigured so that three kinds of frame are deployed in the Y axisdirection based on a fixed frame 20 (discussed below). The lens barrel 3supports a plurality of lens groups so that the plurality of lens groupsare capable of relative movement in the Y axis direction. Theconfiguration of the optical system O and the lens barrel 3 will bediscussed in detail below.

A CCD image sensor 141 (an example of an imaging element; see FIG. 4)and an image recorder (not shown) are built into the shell 2. The CCDimage sensor 141 performs photoelectric conversion on optical images.The image recorder (not shown) records images acquired by the CCD imagesensor 141. As shown in FIG. 2, a liquid crystal monitor 8 is providedon the rear face of the shell 2. The liquid crystal monitor 8 displaysimages acquired by the CCD image sensor 141.

A release button 4, a dial 5, and a zoom adjusting lever 7 are providedon the top face of the shell 2. A power switch 6 is provided on the rearface of the shell 2. The release button 4 is used by the user to controlthe timing of exposure. The dial 5 is used by the user to make varioussettings related to the imaging operation. The power switch 6 is used bythe user to turn the digital camera 1 on or off. The zoom adjustinglever 7 is used by the user to adjust the zoom ratio, and rotates over apredetermined angle range around the release button 4.

A sensor 9 is built into the interior of the shell 2. The sensor 9detects shake in the pitch direction (rotation around the X axis) andthe yaw direction (rotation around the Z axis) of the digital camera 1in order to correct image blurring.

3: Configuration of Optical System and Lens Barrel

The overall configuration of the lens barrel 3 will now be describedthrough reference to FIGS. 3 to 10. FIGS. 3A and 3B are simplifiedoblique views of the lens barrel 3. FIGS. 4 to 7 are exploded obliqueviews of the lens barrel 3. FIG. 3A is a simplified oblique view of thelens barrel 3 when it is retracted (stowed). FIG. 3B is a simplifiedoblique view of the lens barrel 3 during imaging. FIGS. 8 to 10 aresimplified cross sections of the lens barrel 3. FIG. 8 is a crosssection of the retracted position, FIG. 9 is a cross section at the wideangle end, and FIG. 10 is a cross section at the telephoto end.

As shown in FIGS. 8 to 10, the optical system O comprises a first lensgroup G1, a second lens group G2, a third lens group G3 having aretractable lens group G3 a and a correcting lens group G3 b, and afourth lens group G4.

The first lens group G1 is a lens group having a positive power overall,for example, and takes in light from the subject. The second lens groupG2 is a lens group having a negative power overall, for example. Theretractable lens group G3 a retracts in a direction perpendicular to theoptical axis of the second lens group G2 in the retracted state. Thecorrecting lens group G3 b moves an optical image by moving thecorrecting lens group G3 b in a direction perpendicular to the opticalaxis of the second lens group G2. Consequently, the correcting lensgroup G3 b can suppress movement of the optical image in the CCD imagesensor 141 caused by movement of the digital camera 1, for example. Theretractable lens group G3 a and the correcting lens group G3 b aremovable integrally in the direction of the optical axis. The fourth lensgroup G4 is used for adjusting the focal point, for example. The opticalsystem O equipped with these lens groups is supported by the lens barrel3 so as to be capable of relative movement in the Y axis direction.

As shown in FIGS. 3 and 4, the lens barrel 3 comprises the fixed frame20, a zoom motor unit 110, a master flange 10, a drive frame 30, acamera cam frame 40, a rotary cam frame 70, and a rectilinear frame 80.

The fixed frame 20 is fixed to the shell 2. The zoom motor unit 110 (oneexample of a zooming unit) is fixed to the fixed frame 20 and acts as adrive source. The master flange 10 houses various frames between itselfand the fixed frame 20. The drive force of the zoom motor unit 110 isinputted to the drive frame 30. The camera cam frame 40 is supportedmovably in the Y axis direction by the fixed frame 20. The rotary camframe 70 rotates along with the drive frame 30. The rectilinear frame 80moves in the Y axis direction in a state of being unable to rotate withrespect to the fixed frame 20.

The drive frame 30 and the rotary cam frame 70 are movable in the Y axisdirection and rotatable with respect to the fixed frame 20. Othermembers move in the Y axis direction without rotating with respect tothe fixed frame 20. The CCD image sensor 141 is attached to the masterflange 10. An example of the zoom motor unit 110 is a unit composed of aDC motor and a reduction gear.

The lens barrel 3 further comprises a first lens frame 60, a second lensframe 190, a retractable lens frame 250, a correcting lens frame 240, athird lens frame 200, and a fourth lens frame 90.

The first lens frame 60 supports the first lens group G1. The secondlens frame 190 supports the second lens group G2. The retractable lensframe 250 supports the retractable lens group G3 a. More precisely, theretractable lens frame 250 supports the retractable lens group G3 a sothat the retractable lens group G3 a is retracted to a retractedposition. The correcting lens frame 240 supports the image blurcorrecting lens group G3 b. The third lens frame 200 supports theretractable lens frame 250 and the correcting lens frame 240. The fourthlens frame 90 supports the fourth lens group G4.

3.1: Fixed Frame

As shown in FIGS. 4 and 5, the fixed frame 20 is a member for supportingthe drive frame 30 rotatably around the optical axis A andrectilinearly-movably in the Y axis direction. The fixed frame 20 is astationary member in the lens barrel 3 along with the master flange 10.The fixed frame 20 is fixed by screws to the master flange 10, forexample. The fixed frame 20 is equipped with a drive gear 22. The drivegear 22 is rotatably supported by the fixed frame 20.

The drive gear 22 is a member for transmitting the drive force of thezoom motor unit 110 to the drive frame 30. The drive gear 22 engageswith the gear (not shown) of the zoom motor unit 110.

Three cam grooves 23 and three rectilinear grooves 27 disposed at asubstantially equal pitch in the circumferential direction are formed onthe inner peripheral side of the fixed frame 20. Cam pins 34 of thedrive frame 30 are inserted into the cam grooves 23. The rectilineargrooves 27 are used to guide the camera cam frame 40 in the Y axisdirection. Rectilinear protrusions 47 are inserted into the rectilineargrooves 27.

3.2: Drive Frame

As shown in FIGS. 4 and 5, the drive frame 30 is a member for supportingthe camera cam frame 40 rotatably around the optical axis A andintegrally-movably in the Y axis direction. The drive frame 30 isdisposed on the inner peripheral side of the fixed frame 20.

The drive frame 30 mainly has a substantially cylindrical drive framemain body 31, a gear 32, and the three cam pins 34. The drive frame mainbody 31 is disposed between the fixed frame 20 and the camera cam frame40 (discussed below) in the radial direction. A trim ring 160 isattached to the end of the drive frame main body 31 on the Y axisdirection positive side. A light blocking ring (not shown) in the formof a hollow and thin disk is sandwiched between the trim ring 160 andthe drive frame main body 31. The gear 32 is formed on the outerperipheral face of the drive frame main body 31. The gear 32 engageswith the drive gear 22, and the drive force of the zoom motor unit 110is transmitted through the drive gear 22 to the drive frame 30. Thethree cam pins 34 are disposed at a substantially equal pitch in thecircumferential direction around the outer peripheral face of the driveframe main body 31. The three cam pins 34 each fit one of the camgrooves 23 of the fixed frame 20. Consequently, the drive frame 30 movesin the Y axis direction while rotating around the optical axis A withrespect to the fixed frame 20.

A first rotary groove 36, a second rotary groove 37, three rectilineargrooves 38, and three cam grooves 39 are formed on the inner peripheralside of the drive frame main body 31. The first rotary groove 36 is usedto guide first rotary protrusions 43 of the camera cam frame 40 in therotational direction. The second rotary groove 37 is used to guidesecond rotary protrusions 45 in the rotational direction. Therectilinear grooves 38 are used to guide cam pins 76 (discussed below)of the rotary cam frame 70. The three rectilinear grooves 38 aredisposed at a substantially equal pitch in the circumferential directionon the inner peripheral face of the drive frame main body 31.

3.3: Camera Cam Frame

As shown in FIG. 4, the camera cam frame 40 is a member for guiding therotary cam frame 70 (discussed below) in the optical axis direction. Thecamera cam frame 40 is disposed on the inner peripheral side of thedrive frame 30.

As shown in FIG. 5, the camera cam frame 40 mainly has a substantiallycylindrical camera cam frame main body 41 (constitutes the maincomponent), three cam through-grooves 42 formed in the camera cam framemain body 41, three rectilinear through-grooves 48, the three firstrotary protrusions 43, the three second rotary protrusions 45, threerectilinear grooves 46, the three rectilinear protrusions 47, and aflange 44.

The camera cam frame main body 41 is disposed between the fixed frame 20and the rotary cam frame 70. The three cam through-grooves 42 aredisposed at an equal pitch in the circumferential direction. The campins 76 (discussed below) of the rotary cam frame 70 go through thethree cam through-grooves 42 in the radial direction.

The three rectilinear protrusions 47 are disposed at an equal pitch inthe circumferential direction. The three rectilinear protrusions 47 areinserted in the rectilinear grooves 27 of the fixed frame 20, and areguided in the Y axis direction.

The first rotary protrusions 43 and the second rotary protrusions 45 arepositioning protrusions. The first rotary protrusions 43 and the secondrotary protrusions 45 are guided in the rotational direction by thefirst rotary groove 36 and the second rotary groove 37 of the driveframe 30. Consequently, the camera cam frame 40 moves integrally withthe drive frame 30 in the Y axis direction, while rotating as neededwith respect to the drive frame 30. When the drive frame 30 rotates withrespect to the fixed frame 20, the drive frame 30 moves in the Y axisdirection with respect to the fixed frame 20. At this point, the cameracam frame 40 moves along with the drive frame 30 in the Y axis directionwith respect to the fixed frame 20, without rotating with respect to thefixed frame 20 (that is, while rotating relatively with respect to thedrive frame 30).

Second rectilinear protrusions 85 of the rectilinear frame 80 (discussedbelow) are inserted into the three rectilinear grooves 46. Consequently,the rotation of the rectilinear frame 80 is restricted in the rotationaldirection with respect to the camera cam frame 40. The rectilinear frame80 is movable in the Y axis direction.

Rectilinear protrusions 203 of the third lens frame 200 (discussedbelow) are inserted into the three rectilinear through-grooves 48.Consequently, the rotation of the third lens frame 200 is restricted inthe rotational direction with respect to the camera cam frame 40. Thethird lens frame 200 is movable in the Y axis direction.

3.4: Rotary Cam Frame

As shown in FIG. 6, the rotary cam frame 70 is a member for supportingthe first lens frame 60 (discussed below), the second lens frame 190(discussed below), and the aperture unit 230 (discussed below) movablyin the Y axis direction. The rotary cam frame 70 is disposed on theouter peripheral side of the first lens frame 60 and the innerperipheral side of the fixed frame 20. More specifically, the rotary camframe 70 mainly has a substantially cylindrical cam frame main body 71,the three cam pins 76, and three rotary protrusions 75.

The three cam pins 76 are provided on the outer peripheral side of thecam frame main body 71. The three cam pins 76 are disposed at an equalpitch in the circumferential direction.

The three rotary protrusions 75 are formed at the end of the cam framemain body 71 on the Y axis direction negative side. The rotaryprotrusions 75 are molded integrally with the cam frame main body 71.The rotary protrusions 75 protrude inward in the radial direction fromrotary grooves 77. Rotary protrusions 83 of the rectilinear frame 80 aresandwiched between the rotary protrusions 75 and the rotary grooves 77.As a result, movement of the rectilinear frame 80 in the Y axisdirection with respect to the rotary cam frame 70 is restricted.

The distal ends 76 b of the cam pins 76 are inserted into therectilinear grooves 38 (see FIG. 5) of the drive frame 30, so the rotarycam frame 70 is rotatable integrally with the drive frame 30 whilemoving the Y axis direction with respect to the drive frame 30. Also,the cam pins 76 are inserted into the cam through-grooves 42 of thecamera cam frame 40, so when the drive frame 30 and the camera cam frame40 rotate relatively, the rotary cam frame 70 and the camera cam frame40 also rotate relatively. In this case, the cam pins 76 move along thecam through-grooves 42. As a result, the rotary cam frame 70 rotatesalong with the drive frame 30 while moving in the Y axis direction withrespect to the drive frame 30, according to the shape of the camthrough-grooves 42.

With the above configuration, the rotary cam frame 70 rotates integrallywith the drive frame 30, and moves in the Y axis direction with respectto the drive frame 30. Specifically, the rotary cam frame 70 can rotatewith respect to the fixed frame 20 while moving in the Y axis direction.The amount of movement of the rotary cam frame 70 in the Y axisdirection is the sum of the amount of movement of the drive frame 30 inthe Y axis direction with respect to the fixed frame 20, plus the amountof movement of the rotary cam frame 70 in the Y axis direction withrespect to the drive frame 30.

3.4.1: Configuration of First Cam Grooves 72, Second Cam Grooves 73, andThird Cam Grooves 74

As shown in FIG. 6, three first cam grooves 72, three second cam grooves73, and three third cam grooves 74 are formed on the inner peripheralside of the cam frame main body 71. Cam pins 68 of the first lens frame60 are inserted into the first cam grooves 72. Consequently, the rotarycam frame 70 movably supports the first lens frame 60. With thisconfiguration, when the rotary cam frame 70 rotates with respect to thefirst lens frame 60, the cam pins 68 are guided by the first cam grooves72. As a result, the first lens frame 60 moves in the Y axis directionwith respect to the rotary cam frame 70.

Also, since the cam pins 235 (discussed below) of the aperture unit 230are inserted into the second cam grooves 73, when the rotary cam frame70 rotates with respect to the aperture unit 230, the cam pins 235 areguided by the second cam grooves 73.

Also, cam pins 192 (discussed below) of the second lens frame 190 areinserted into the third cam grooves 74. Consequently, when the rotarycam frame 70 rotates with respect to the second lens frame 190, the campins 192 are guided by the third cam grooves 74. As a result, the secondlens frame 190 move in the Y axis direction with respect to the rotarycam frame 70.

3.5: Rectilinear Frame

As shown in FIG. 6, the rectilinear frame 80 mainly has a rectilinearframe main body 81, a flange 87, three first rectilinear protrusions 82,three second rectilinear protrusions 85, three rectilinear grooves 84,three rectilinear grooves 88, and three rotary protrusions 83. Therectilinear frame 80 is disposed between the first lens frame 60 and thesecond lens frame 190 (discussed below) in the radial direction.

The flange 87 protrudes on the outer peripheral side and on the Y axisdirection negative side of the rectilinear frame main body 81, and isformed integrally with the rectilinear frame main body 81. The threefirst rectilinear protrusions 82 are provided on the outer peripheralpart of the rectilinear frame main body 81, and protrude outward in theradial direction from the rectilinear frame main body 81. The threefirst rectilinear protrusions 82 are disposed at an equal pitch in thecircumferential direction. The three first rectilinear protrusions 82are inserted into first rectilinear grooves 63 (discussed below) of thefirst lens frame 60. The second rectilinear protrusions 85 are moldedintegrally with the flange 87 on the end of the flange 87 in the Y axisnegative direction, and protrude outward in the radial direction fromthe flange 87. The second rectilinear protrusions 85 are inserted intothe rectilinear grooves 46 (see FIG. 5) of the camera cam frame 40.Consequently, the rectilinear frame 80 moves in the Y axis directionwithout rotating with respect to the camera cam frame 40.

The rectilinear grooves 84 are through-grooves that pass through in theradial direction, and extend in the Y axis direction. The threerectilinear grooves 84 are disposed at an equal pitch in thecircumferential direction. Three rectilinear protrusions 191 of thesecond lens frame 190 (discussed below) are inserted into the threerectilinear grooves 84.

The rectilinear grooves 88 are through-grooves that pass through in theradial direction, and extend in the Y axis direction. The threerectilinear grooves 88 are disposed at a substantially equal pitch inthe circumferential direction. The three rectilinear protrusions 234(discussed below) of the aperture unit 230 are inserted into therectilinear grooves 88.

The first lens frame 60 and the second lens frame 190 are movable in theY axis direction with respect to the rectilinear frame 80 withoutrotating with respect to the rectilinear frame 80. This motion isimplemented by the first rectilinear protrusions 82 and the rectilineargrooves 84. Specifically, the first lens frame 60 and the second lensframe 190 are movable in the Y axis direction without rotating withrespect to the fixed frame 20.

The three rotary protrusions 83 are inserted into the rotary grooves 77of the rotary cam frame 70. The rotary cam frame 70 is rotatable withrespect to the rectilinear frame 80 and to move integrally in the Y axisdirection. This motion is implemented by the rotary grooves 77 and therotary protrusions 75.

Sloped protrusions 89 function as drive protrusions for pushing a lever(not shown) that opens and closes the lens barrier 50 in the rotationaldirection. The sloped protrusions 89 are configured so that barriervanes 51 (see FIG. 3A) close when the opening/closing lever has rotatedto a retracted position that the lens barrier 50 is closest to therectilinear frame 80 in the Y axis direction.

FIG. 11 is an oblique view of the retractable lens frame 250 and therectilinear frame 80. FIG. 12A is a plan view of the retracted state ofthe retractable lens frame 250. FIG. 12B is a plan view of when theretractable lens frame 250 is in an imaging state. As shown in FIGS. 6and 11, the rectilinear frame 80 has the rectilinear frame main body 81.A sloped face 86 a, a rectilinear restricting face 86 b, and an end face86 c are provided on the inner peripheral side of the rectilinear framemain body 81. The sloped face 86 a is a cam face that rotates a driveprotrusion 255 of the retractable lens frame 250 (discussed below). Therectilinear restricting face 86 b further rotates the drive protrusion255 so as to retract the retractable lens group G3 a of the retractablelens frame 250 to the retracted position (see FIG. 12A). The end face 86c drives the drive protrusion 255 to the Y axis direction negative side.

Thus, the rectilinear frame main body 81 (86 a, 86 b, 86 c) of therectilinear frame 80, for example, has a mechanism 400 (retraction drivemechanism) that retracts the retractable lens group G3 a to theretracted position. To summarize the above, the retraction drivemechanism 400 disposes the optical axis of the retractable lens group G3a to a position a specific distance away from the optical axis of thecorrecting lens group G3 b (retracted position), and thereby retractsthe retractable lens group G3 a.

3.6: First Lens Frame

As shown in FIGS. 4, 6, and 7, the first lens frame 60 is a member forsupporting the first lens group G1. The first lens frame 60 is disposedon the inner peripheral side of the camera cam frame 40. Morespecifically, the first lens frame 60 mainly has a first lens frame mainbody 61 and a flange 62 to which the first lens group G1 is fixed. Theflange 62 is provided to the end of the first lens frame main body 61 onthe Y axis direction positive side. One first opening 67 a and sixsecond openings 67 b that pass through in the Y axis direction areformed in the flange 62. A lever (not shown) for opening and closing thelens barrier 50 is inserted into the first opening 67 a so as to bemovable in the rotational direction during telescoping. The lens barrier50 is fixed on the Y axis direction positive side of the first lensframe 60. As shown in FIG. 7, the lens barrier 50 and the first lensframe 60 are covered by a trim ring 180.

As shown in FIG. 6, the three first rectilinear grooves 63 are providedon the inner peripheral side of the first lens frame main body 61. Thethree cam pins 68 are provided on the outer peripheral side of the firstlens frame main body 61.

The first rectilinear grooves 63 are guided by the first rectilinearprotrusions 82 of the rectilinear frame 80. Consequently, the first lensframe 60 moves in the Y axis direction without rotating with respect tothe rectilinear frame 80. Specifically, the first lens frame 60 issupported by the rectilinear frame 80 and the camera cam frame 40 so asto be movable in the Y axis direction without rotating with respect tothe fixed frame 20.

The cam pins 68 are guided by the first cam grooves 72 of the rotary camframe 70. Consequently, the first lens frame 60 is supported by therotary cam frame 70 so as to be movable in the Y axis direction whilerotating with respect to the rotary cam frame 70.

3.7: Second Lens Frame

The second lens frame 190 is a member for supporting the second lensgroup G2 movably in the Y axis direction. The second lens frame 190 isdisposed on the inner peripheral side of the rectilinear frame 80. Morespecifically, as shown in FIG. 6, the second lens frame 190 mainly has asecond lens frame main body 193 that supports the second lens group G2,the three rectilinear protrusions 191 formed on the outer peripheralpart of the second lens frame main body 193, and the three cam pins 192provided on the outer peripheral side of the rectilinear protrusions191.

The rectilinear protrusions 191 are flat protrusions that extend in theY axis direction, and are disposed at positions corresponding to therectilinear grooves 84 of the rectilinear frame 80. The threerectilinear protrusions 191 are disposed at an equal pitch in thecircumferential direction. The second lens frame 190 are movable in theY axis direction without rotating with respect to the rectilinear frame80. This motion is implemented by the rectilinear grooves 84 and therectilinear protrusions 191.

The cam pins 192 protrude outward in the radial direction from the endsof the rectilinear protrusions 191 (more precisely, the ends on the Yaxis direction negative side). The cam pins 192 are fitted into thethird cam grooves 74 of the rotary cam frame 70.

With the above configuration, the second lens frame 190 is movable inthe Y axis direction, according to the shape of the third cam grooves74, without rotating with respect to the fixed frame 20.

3.8: Aperture Unit

The aperture unit 230 is a mechanism for adjusting the quantity oflight. As shown in FIGS. 9 and 10, the aperture unit 230 is disposedbetween the second lens group G2 and the retractable lens group G3 a inthe imaging state. In the imaging state, the aperture unit 230 and theretractable lens group G3 a are movable independently of each other inthe direction of the optical axis. Also, in the imaging state, theaperture unit 230 and the second lens group G2 are movable independentlyof each other in the direction of the optical axis.

As shown in FIG. 14, the aperture unit 230 mainly has an aperture mainbody 231, the three rectilinear protrusions 234, the three cam pins 235,an aperture motor 232 for driving aperture vanes (not shown), and ashutter motor 233 for driving shutter vanes (not shown).

The three rectilinear protrusions 234 are formed on the outer peripheralpart of the aperture main body 231. The rectilinear protrusions 234 areguided by the rectilinear grooves 88 of the rectilinear frame 80.Consequently, the aperture unit 230 is movable in the Y axis directionwithout rotating with respect to the rectilinear frame 80.

The three cam pins 235 are provided on the outer peripheral side of therectilinear protrusions 234. The cam pins 235 are fitted into the secondcam grooves 73 of the rotary cam frame 70.

With the above configuration, the aperture unit 230 is movable in the Yaxis direction while following the shape of the second cam grooves 73,without rotating with respect to the fixed frame 20. Consequently, theaperture unit 230 can be disposed at the optimal position between thesecond lens group G2 and the retractable lens group G3 a. The optimalposition is a position at which the aperture opening diameter and thelens group diameter are smaller. As a result, a more compact lens barrelcan be obtained.

The aperture motor 232 is a stepping motor, for example. The aperturemotor 232 can change the aperture value of the optical system O bydriving the aperture vanes (not shown) in the opening direction or theclosing direction. Also, the shutter motor 233 can vary the exposuretime by changing the timing at which the shutter vanes (not shown) aredriven from their open state to their closed state.

3.9: Third Lens Frame

As shown in FIG. 4, the third lens frame 200 constitutes a shakecorrection device, and is disposed on the inner peripheral side of therectilinear frame 80. The shake correction device shown here serves tosuppress movement of the optical image with respect to the CCD imagesensor 141. The movement of the optical image is caused by movement ofthe shell 2.

The third lens frame 200 is movable integrally in the Y axis direction,and supports the third lens group G3 movably in a plane perpendicular tothe optical axis. More specifically, as shown in FIGS. 12 and 13, thethird lens frame 200 mainly has a base frame 201, the retractable lensframe 250 that supports the retractable lens group G3 a, the correctinglens frame 240 that supports the correcting lens group G3 b, aretraction main axis cover 270, and a torsion compression coil spring258.

The correcting lens group G3 b is supported movably in a directionperpendicular to the optical axis A by an image blur correcting lenssupport mechanism 290 such as the correcting lens frame 240 and the baseframe 201.

As shown in FIG. 13, the base frame 201 has a substantially cylindricalbase frame main body 206, the three rectilinear protrusions 203, threecam pins 204, a rotary shaft 211, a restricting shaft 214, a firstsupport shaft 212, and a second support shaft 213. The three rectilinearprotrusions 203 extend outward in the radial direction from the outerperipheral part of the base frame main body 206. The rectilinearprotrusions 203 are flat protrusions that extend in the Y axisdirection. These rectilinear protrusions 203 are inserted into therectilinear through-grooves 48 of the camera cam frame 40. The cam pins204 protrude outward in the radial direction from the outer peripheralpart of the rectilinear protrusions 203. The cam pins 204 are fittedinto the cam grooves 39 of the drive frame 30.

The rotary shaft 211, the restricting shaft 214, the first support shaft212, and the second support shaft 213 are fixed to the base frame 201.The rotary shaft 211 supports the correcting lens frame 240 rotatablyaround the axis of the rotary shaft 211. The restricting shaft 214restricts the movement range of the correcting lens frame 240 withrespect to the base frame 201 (more precisely, the movement range in theZ axis direction and the X axis direction perpendicular to the opticalaxis A). The restricting shaft 214 is inserted into a restrictor 247(see FIG. 12B) formed on a support frame main body 241.

The first support shaft 212 and the second support shaft 213 support thecorrecting lens frame 240 movably within a plane perpendicular to theoptical axis A. The first support shaft 212 and the second support shaft213 restrict the movement range of the correcting lens frame 240 in theY axis direction with respect to the base frame 201. Both ends of thefirst support shaft 212 are fixed to the base frame main body 206. Thesecond support shaft 213 is fanned shorter than the first support shaft212, and one end of the second support shaft 213 is fixed to the baseframe main body 206.

The correcting lens frame 240 is supported by the base frame 201 movablyin the pitch direction (such as the X axis direction) and the yawdirection (such as the Z axis direction). More specifically, thecorrecting lens frame 240 has the support frame main body 241, a firstguide component 242, a pair of second guide components 245, a thirdguide component 246, and the restrictor 247. The correcting lens groupG3 b is fixed to the correcting lens frame 240.

The first guide component 242 is a slender groove that extends in the Xaxis direction. The rotary shaft 211 is inserted into the first guidecomponent 242. The correcting lens frame 240 is movable in the X axisdirection and rotate around the center of the rotary shaft 211 withrespect to the third lens frame 200. This motion is implemented by thefirst guide component 242 and the rotary shaft 211.

The pair of second guide components 245 are L-shaped portions that slidewith the first support shaft 212. The second guide components 245protrude in the X axis direction from the base frame 201. The secondguide components 245 are spaced apart in the Z axis direction. The firstsupport shaft 212 is inserted between the support frame main body 241and the second guide components 245. The second guide components 245 andthe first support shaft 212 restrict the movement of the correcting lensframe 240 in the Y axis direction with respect to the third lens frame200.

The third guide component 246 is an L-shaped portion that slides withthe second support shaft 213. The second support shaft 213 is insertedbetween the support frame main body 241 and the third guide component246. The third guide component 246 and the second support shaft 213restrict the movement of the correcting lens frame 240 in the Y axisdirection with respect to the third lens frame 200.

The third lens frame 200 further has a pitch coil 221, a pitch magnet244, and a pitch position sensor 223 in order to move the correctinglens group G3 b in the pitch direction (an example of a first direction)that is perpendicular to the optical axis A. In this embodiment, thepitch coil 221 is fixed to the base frame 201. The pitch magnet 244 isadhesively fixed, for example, to the correcting lens frame 240. Thepitch position sensor 223 is fixed to the base frame 201.

The third lens frame 200 further has a yaw coil 220, a yaw magnet 243,and a yaw position sensor 222 in order to move the correcting lens groupG3 b in the yaw direction (the Z axis direction; an example of a seconddirection) that is perpendicular to the optical axis A. In thisembodiment, the yaw coil 220 is fixed to the base frame 201. The yawmagnet 243 is adhesively fixed, for example, to the correcting lensframe 240. The yaw position sensor 222 is fixed to the base frame 201.

The third lens frame 200 further has a rotary shaft 224 that protrudeson the Y axis direction positive side of the base frame 201, and astopper 205 consisting of a substantially rectangular protrusion. Therotary shaft 224 is inserted into a guide hole 253 in the retractablelens frame 250 (discussed below). The stopper 205 is provided in orderto position to the retractable lens frame 250. In a state in which thestopper 205 is in contact with a positioning protrusion 256 (discussedbelow) of the retractable lens frame 250, the optical axis C of theretractable lens group G3 a coincides with the optical axis A.

3.9.1: Retractable Lens Frame

The retractable lens frame 250 supports the retractable lens group G3 aretractably out of the optical path of the optical system O. Morespecifically, as shown in FIGS. 12 and 13, the retractable lens frame250 has a lens frame main body 251, a linking arm 254, a cylinder 252,the drive protrusion 255, and the positioning protrusion 256.

The lens frame main body 251 supports the retractable lens group G3 a.The linking arm 254 extends outside from lens frame main body 251. Thecylinder 252 is provided at the end of the linking arm 254. The cylinder252 is linked with the lens frame main body 251 by the linking arm 254.The cylinder 252 has the guide hole 253. The rotary shaft 224 of thebase frame 201 is inserted into the guide hole 253.

The cylinder 252 is inserted into the torsion compression coil spring258. This torsion compression coil spring 258 keeps the retractable lensframe 250 pressed to the R3 side with respect to the base frame 201.Also, this torsion compression coil spring 258 keeps the retractablelens frame 250 pressed to the Y axis direction positive side withrespect to the base frame 201.

The drive protrusion 255 extends from the outer peripheral part of thecylinder 252 in the opposite direction from the linking arm 254. Thepositioning protrusion 256 extends from the outer peripheral part of thelens frame main body 251 in a direction substantially perpendicular tothe linking arm 254. The positioning protrusion 256 is pressed againstthe stopper 205 by the torsion compression coil spring 258.

The retraction main axis cover 270 is a member that keeps theretractable lens frame 250 from coming loose. The retraction main axiscover 270 is fixed to the base frame 201 by a screw 271.

3.10: Fourth Lens Frame

As shown in FIG. 4, the fourth lens frame 90 is a member for supportingthe fourth lens group G4 movably in the Y axis direction. The fourthlens frame 90 is supported movably in the Y axis direction by two shafts11 a and 11 b formed on the master flange 10. The drive of the fourthlens frame 90 is performed by a focus motor 120 fixed to the masterflange 10. When the fourth lens frame 90 is driven by the focus motor120, the fourth lens frame 90 moves in the Y axis direction with respectto the master flange 10. This allows the focus to be adjusted in theoptical system O.

3.11: Imaging Element Unit

As shown in FIG. 4, an imaging element unit 140 has an IR absorbingglass (not shown), the CCD image sensor 141, and a CCD plate 142.

The master flange 10 is fixed to the fixed frame 20, and is disposed onthe Y axis direction negative side of the fixed frame 20. A rectangularopening 12 is formed in the master flange 10. The optical image foistedby the optical system O passes through the opening 12 and is imaged onthe light receiving face of the CCD image sensor 141.

The IR absorbing glass (not shown) is a flat and rectangular member thatis smaller than the opening 12, and is disposed within the opening 12.The IR absorbing glass subjects light passing through the opening 12 toinfrared absorption processing (an example of optical processing). TheCCD image sensor 141 converts the light transmitted by the IR absorbingglass (not shown) into an electrical signal.

4: Operation of Digital Camera

The operation of the digital camera 1 will be described throughreference to FIGS. 1 to 3.

4.1: When Power is Off

When the power switch 6 is in its off position, the lens barrel 3 isstopped in its retracted state (the state shown in FIG. 8, in which thelength of the lens barrel 3 in the Y axis direction is shortest) so thatthe lens barrel 3 fits within the external dimensions of the shell 2 inthe Y axis direction. In this state, the lens barrier 50 of the lensbarrel 3 is closed.

Also, in this state, the rectilinear restricting face 86 b of therectilinear frame 80 pushes the drive protrusion 255 of the retractablelens frame 250 to the R4 side around the center axis B of the rotaryshaft 224. Accordingly, the retractable lens group G3 a stops at aretracted position that is out of the optical axis A (see FIGS. 11 and12A). Also, the end face 86 c of the rectilinear frame 80 holds thedrive protrusion 255 of the retractable lens frame 250 to the Y axisdirection negative side. In other word, the drive protrusion 255 of theretractable lens frame 250 is positioned on the end face 86 c of therectilinear frame 80 when the state of the lens barrel 3 changes fromthe imaging state (see FIG. 9) to the retracted state. Consequently, thedistance between the retractable lens frame 250 and the shutter unit 230is shorter than in the imaging state (see FIG. 9).

4.2: Operation When Power is On

4.2.1: Operation of the Lens Barrel

When the power switch 6 is switched on, power is supplied to the variouscomponents and the lens barrel 3 is driven from its retracted state toits imaging state. More specifically, the drive frame 30 is driven bythe zoom motor unit 110 by a specific angle with respect to the fixedframe 20. As a result, the drive frame 30 moves along the cam grooves 23to the Y axis direction positive side with respect to the fixed frame 20while rotating with respect to the fixed frame 20.

When the drive frame 30 moves in the Y axis direction while rotatingwith respect to the fixed frame 20, the first rotary protrusions 43 andthe second rotary protrusions 45 cause the camera cam frame 40 to moveintegrally with the drive frame 30 in the Y axis direction. At thispoint, since the rectilinear protrusions 47 of the camera cam frame 40are guided in the Y axis direction by the rectilinear grooves 27 of thefixed frame 20. Consequently, the camera cam frame 40 moves integrallywith the drive frame 30 in the Y axis direction without rotating withrespect to the fixed frame 20 (see FIG. 5).

Also, the distal ends 76 b of the cam pins 76 of the rotary cam frame 70are fitted into the rectilinear grooves 38 of the drive frame 30, so therotary cam frame 70 rotates along with the drive frame 30 with respectto the fixed frame 20. As a result, the rotary cam frame 70 and thecamera cam frame 40 rotate relatively. Also, the cam pins 76 of therotary cam frame 70 go through the cam through-grooves 42 of the cameracam frame 40, so when the rotary cam frame 70 rotates with respect tothe camera cam frame 40, the rotary cam frame 70 moves in the Y axisdirection while rotating with respect to the camera cam frame 40 and thefixed frame 20, according to the shape of the cam through-grooves 42(see FIGS. 5 and 6).

The rectilinear frame 80 is provided to be rotatable with respect to therotary cam frame 70 and integrally movable in the Y axis direction. Therectilinear frame 80 is provided to be movable in the Y axis directionwithout rotating with respect to the camera cam frame 40. Morespecifically, the rotary protrusions 83 of the rectilinear frame 80 areinserted into the rotary grooves 77 of the rotary cam frame 70, and thesecond rectilinear protrusions 85 of the rectilinear frame 80 areinserted into the rectilinear grooves 46 of the camera cam frame 40.With this constitution, when the rotary cam frame 70 moves in the Y axisdirection while rotating with respect to the fixed frame 20, therectilinear frame 80 moves in the Y axis direction integrally with therotary cam frame 70 without rotating with respect to the fixed frame 20and the camera cam frame 40 (see FIGS. 5 and 6).

Furthermore, when the rotary cam frame 70 rotates with respect to thefixed frame 20, the cam pins 68 of the first lens frame 60 are guided inthe Y axis direction by the first cam grooves 72 of the rotary cam frame70. Accordingly, the first lens frame 60 moves in the Y axis directionwith respect to the rotary cam frame 70 and the rectilinear frame 80.Since the first rectilinear grooves 63 of the first lens frame 60 areinserted into the first rectilinear protrusions 82 of the rectilinearframe 80 here, the first lens frame 60 moves in the Y axis directionwithout rotating with respect to the rectilinear frame 80. Therefore,the first lens frame 60 moves in the Y axis direction according to theshape of the first cam grooves 72 without rotating with respect to thefixed frame 20 (while rotating with respect to the rotary cam frame 70).

The cam pins 192 of the second lens frame 190 are fitted into the thirdcam grooves 74 of the rotary cam frame 70. Since the rectilinearprotrusions 191 of the second lens frame 190 are inserted into therectilinear grooves 84 of the rectilinear frame 80, the second lensframe 190 moves in the Y axis direction without rotating with respect tothe rectilinear frame 80. With this constitution, the second lens frame190 moves in the Y axis direction according to the shape of the thirdcam grooves 74, without rotating with respect to the camera cam frame 40and the fixed frame 20.

Also, the cam pins 235 of the aperture unit 230 are fitted into thesecond cam grooves 73 of the rotary cam frame 70. The rectilinearprotrusions 234 of the aperture unit 230 are inserted into therectilinear grooves 88 of the rectilinear frame 80. Consequently, theaperture unit 230 moves in the Y axis direction without rotating withrespect to the rectilinear frame 80. With this configuration, theaperture unit 230 moves in the Y axis direction according to the shapeof the second cam grooves 73, without rotating with respect to thecamera cam frame 40 and the fixed frame 20.

Also, since the rectilinear protrusions 203 of the third lens frame 200are inserted into the rectilinear through-grooves 48 of the camera camframe 40, the third lens frame 200 is movable in the Y axis directionwithout rotating with respect to the fixed frame 20 and the camera camframe 40. Furthermore, the cam pins 204 are fitted into the cam grooves39 of the drive frame 30. With this constitution, the third lens frame200 moves in the Y axis direction according to the shape of the camgrooves 39, without rotating with respect to the camera cam frame 40 andthe fixed frame 20.

As shown in FIGS. 8 and 9, when the zoom motor unit drives the lensbarrel 3 from the retracted state to the imaging state, the drive frame30 moves to the Y axis direction positive side while rotating withrespect to the fixed frame 20. Meanwhile, the third lens frame 200 movesto the Y axis direction negative side with respect to the drive frame30. Accordingly, the third lens frame 200 moves to the Y axis directionpositive side with respect to the fixed frame 20, but the amount ofmovement of the third lens frame 200 is limited with respect to thefixed frame 20.

Meanwhile, since the second rectilinear protrusions 85 of therectilinear frame 80 are inserted into the rectilinear grooves 46 of thecamera cam frame 40, the rectilinear frame 80 is movable in the Y axisdirection without rotating with respect to the fixed frame 20 and thecamera cam frame 40. Furthermore, since the rotary protrusions 83 of therectilinear frame 80 are meshed with the rotary protrusions 75 of therotary cam frame 70, the rectilinear frame 80 moves in the Y axisdirection along with the rotary cam frame 70 in a state in whichrelative rotation is permitted. When the drive frame 30 rotates withrespect to the fixed frame 20, the rotary cam frame 70 rotates withrespect to the camera cam frame 40, and the cam pins 76 of the rotarycam frame 70 are guided by the cam through-grooves 42 of the camera camframe 40. Consequently, the rectilinear frame 80 moves in the Y axisdirection along with the rotary cam frame 70 without rotating withrespect to the fixed frame 20 and the camera cam frame 40. Morespecifically, the rectilinear frame 80 moves to the Y axis directionpositive side along with the rotary cam frame 70 without rotating withrespect to the fixed frame 20. The movement amount of the rectilinearframe 80 with respect to the fixed frame 20 here is greater than themovement amount of the third lens frame 200 with respect to the fixedframe 20, so in the course of switching the lens barrel 3 from itsretracted state to its imaging state, the rectilinear frame 80 movesaway from the third lens frame 200 to the Y axis direction positiveside.

As the rectilinear frame 80 thus moves away from the third lens frame200, the retractable lens frame 250 moves to the Y axis directionpositive side along with the rectilinear frame 80 in a state in whichthe drive protrusion 255 is pressed against the end face 86 c of therectilinear frame 80. At this point the retractable lens frame 250 movesto the Y axis direction positive side with respect to the base frame201. When the retractable lens frame 250 hits the retraction main axiscover 270, movement of the retractable lens frame 250 in the Y axisdirection with respect to the base frame 201 stops, and the rectilinearframe 80 moves away from the retractable lens frame 250 to the Y axisdirection positive side.

As the rectilinear frame 80 moves away from the retractable lens frame250 to the Y axis direction positive side, the drive protrusion 255 ofthe retractable lens frame 250 moves to the inclined face 86 a whilesliding with the rectilinear restriction face 86 b of the rectilinearframe 80, and further slides with the inclined face 86 a. At this point,since the drive protrusion 255 is pressed against the inclined face 86 aby the torsional force of the torsion compression coil spring 258, theretractable lens frame 250 rotates from the retracted position to theinsertion position on the R3 side, according to the shape of theinclined face 86 a. The retractable lens frame 250 is positioned at theposition where the positioning protrusion 256 hits the stopper 205 (thatis, the insertion position) by the torsional force of the torsioncompression coil spring 258 (see FIGS. 11 and 12B). At the insertionposition, the optical axis C of the retractable lens group G3 asubstantially coincides with the optical axis A of the optical system O.Here, a state in which “the optical axis C of the retractable lens groupG3 a substantially coincides with the optical axis A of the opticalsystem O” includes not only a state in which the optical axis Ccoincides completely with the optical axis A, but also a state in whichthe optical axis C is offset from the optical axis A within a range thatis permissible by optical design.

As discussed above, when drive force is inputted to the drive frame 30during telescoping operation, the drive frame 30 moves in the Y axisdirection with respect to the fixed frame 20, and the various componentssupported by the drive frame 30 move in the Y axis direction withrespect to the fixed frame 20. When the drive frame 30 rotates by aspecific angle, rotation of the drive frame 30 stops, and the first lensframe 60, the second lens frame 190, and the third lens frame 200 stopat the wide angle end. As a result of the above operation, the lensbarrel 3 enters an imaging state (such as the state shown in FIG. 9),and imaging with the digital camera 1 becomes possible.

4.3: Zoom Operation During Imaging

4.3.1: Operation on Telephoto Side

When the zoom adjusting lever 7 is moved to the telephoto side, the zoommotor unit 110 drives the drive frame 30 with respect to the fixed frame20 according to the rotational angle and operation duration of the zoomadjusting lever 7. As a result, the rotary cam frame 70 moves to the Yaxis direction positive side with respect to the drive frame 30 whilerotating along with the drive frame 30. At this point, the drive frame30 moves slightly in the Y axis direction along the cam grooves 23 whilerotating with respect to the fixed frame 20.

Also, the first lens frame 60 mainly moves to the Y axis directionpositive side without rotating with respect to the fixed frame 20.Meanwhile, the second lens frame 190 and the aperture unit 230 movemainly to the Y axis direction negative side without rotating withrespect to the fixed frame 20. Furthermore, the third lens frame 200moves mainly to the Y axis direction positive side without rotating withrespect to the fixed frame 20. At this point the retractable lens frame250 and the correcting lens support mechanism 290 move integrally to theY axis direction positive side. As a result of these operations, thezoom ratio of the optical system O gradually increases. When the lensbarrel 3 reaches the telephoto end, the lens barrel 3 stops in the stateshown in FIG. 10.

In the above operation, since a state is maintained in which theinclined face 86 a of the rectilinear frame 80 is separated from thedrive protrusion 255, the retractable lens frame 250 is in a state ofbeing stopped at the insertion position.

4.3.2: Operation on Wide Angle Side

When the zoom adjusting lever 7 is moved to the wide angle side, thedrive frame 30 is driven by the zoom motor unit 110 to the R1 side withrespect to the fixed frame 20 according to the rotational angle andoperation duration of the zoom adjusting lever 7. As a result, therotary cam frame 70 moves to the Y axis direction negative side withrespect to the drive frame 30 while rotating along with the drive frame30. The drive frame 30 here moves slightly in the Y axis direction alongthe cam grooves 23 while rotating with respect to the fixed frame 20.

Also, the first lens frame 60 mainly moves to the Y axis directionnegative side without rotating with respect to the fixed frame 20.Meanwhile, the second lens frame 190 and the aperture unit 230 movemainly to the Y axis direction positive side without rotating withrespect to the fixed frame 20. Further, the third lens frame 200 movesmainly to the Y axis direction negative side without rotating withrespect to the fixed frame 20. At this point, the retractable lens frame250, the correcting lens support mechanism 290, and the aperture unit230 move integrally to the Y axis direction negative side. As a resultof these operations, the zoom ratio of the optical system O graduallydecreases. When the lens barrel 3 reaches the wide angle end, the lensbarrel 3 stops in the state shown in FIG. 9.

Just as with operation on the telephoto side, in the above operation,since a state is maintained in which the inclined face 86 a of therectilinear frame 80 is separated from the drive protrusion 255, theretractable lens frame 250 is in a state of being stopped at theinsertion position.

5: Features

The features of the lens barrel 3 described above are compiled below.The lens barrel 3 comprises the zoom optical system O and the apertureunit 230 (light quantity adjusting mechanism). The zoom optical system Ois configured to have, in order from the subject side, the second lensgroup G2 (one example of a first lens group), the retractable lens groupG3 a (one example of a second lens group), and the correcting lens groupG3 b (one example of a third lens group). The correcting lens group G3 bis configured to move an optical image by moving in a directionperpendicular to the optical axis of the second lens group G2. Theaperture unit 230 is configured to be disposed between the second lensgroup G2 and the retractable lens group G3 a and adjusts the quantity oflight passing through the zoom optical system O. This lens barrel 3 isconfigured to be in an imaging state or a retracted state. In theimaging state, the second lens group G2, the retractable lens group G3a, and the third lens group G3 b are configured to be aligned in thedirection of the optical axis. In this state, during zooming theretractable lens group G3 a and the third lens group G3 b are configuredto move integrally in the direction of the optical axis. Also, in thisstate, during zooming the aperture unit 230 and the retractable lensgroup G3 a are configured to move independently of each other in thedirection of the optical axis. In the retracted state, the retractablelens group G3 a is configured to retract in a direction perpendicular tothe optical axis of the second lens group G2 when viewed in thedirection of the optical axis.

In an embodiment of the present invention, since the retractable lensgroup G3 a can be retracted even though a blur correction mechanism isprovided inside the lens barrel 3, the lens barrel 3 can be made morecompact.

Furthermore, during zooming the aperture unit 230 can be movedindependently of the other lens groups, so the aperture unit 230 and theother lens groups can be made more compact.

Other Embodiments

Embodiments of the present technology are not limited to what was givenabove, and various changes and modifications are possible withoutdeparting from the gist of the technology. Those components havingsubstantially the same configuration and function as in the aboveembodiment are numbered the same as in the above embodiment, and willnot be described in detail again.

The constitution of the optical system O is not limited to that givenabove. For example, the various lens groups may be constituted by asingle lens, or may be constituted by a plurality of lenses.

In the above embodiment, interference between the second lens frame mainbody 193 and the retractable lens frame 250 in a retracted state isprevented by using the rectilinear frame 80 to move the retractable lensframe 250 to the Y axis direction negative side. However, furtherreduction in the size of the lens barrel 3 is also possible even if theretractable lens frame 250 is not moved in the Y axis direction.

In the above embodiment, the aperture unit 230 comprises an aperturemechanism and a shutter mechanism, but the shutter mechanism need not beintegrated with the aperture unit 230, and may be disposed independentlyin a separate location.

The aperture unit 230 doesn't need to be an iris that can change itsopening diameter, and may instead be a fixed aperture. Alternatively,the aperture unit 230 may be a type in which an ND (neutral density)filter made up of a thin film is inserted to cut out light.

In the above embodiment, a digital still camera was described as anexample of a device in which the lens barrel 3 is installed, but thedevice in which the lens barrel 3 is installed may be any device withwhich an optical image needs to be formed. Examples of devices in whichthe lens barrel 3 is installed include an imaging device capable ofcapturing only still pictures, an imaging device capable of capturingonly moving pictures, and an imaging device capable of capturing bothstill and moving pictures.

General Interpretation of Terms

In understanding the scope of the present disclosure, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. Also as used herein to describe theabove embodiment(s), the following directional terms “forward”,“rearward”, “above”, “downward”, “vertical”, “horizontal”, “below” and“transverse” as well as any other similar directional terms refer tothose directions of the lens barrel. Accordingly, these terms, asutilized to describe the present invention should be interpretedrelative to the lens barrel.

The term “configured” as used herein to describe a component, section,or part of a device includes hardware and/or software that isconstructed and/or programmed to carry out the desired function.

The term “zooming” or the phrase “zooming operation” as used hereinrefers to the process of moving the lens group(s) to compensate for thechange in the position of the focal plane while changing magnification.

The terms of degree such as “substantially”, “about” and “approximately”as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, the size, shape, location ororientation of the various components can be changed as needed and/ordesired. Components that are shown directly connected or contacting eachother can have intermediate structures disposed between them. Thefunctions of one element can be performed by two, and vice versa. Thestructures and functions of one embodiment can be adopted in anotherembodiment. It is not necessary for all advantages to be present in aparticular embodiment at the same time. Every feature which is uniquefrom the prior art, alone or in combination with other features, alsoshould be considered a separate description of further inventions by theapplicant, including the structural and/or functional concepts embodiedby such feature(s). Thus, the foregoing descriptions of the embodimentsaccording to the present invention are provided for illustration only,and not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

INDUSTRIAL APPLICABILITY

The present technology is useful in the field of optical devices. Thelens barrel pertaining to the present technology allows a reduction insize.

What is claimed is:
 1. A lens barrel comprising: a zoom optical systemhaving an optical axis and configured to form an optical image of asubject, the zoom optical system including a first lens group, a secondlens group, and a third lens group, the third lens group being movablein a direction perpendicular to the optical axis and configured to movethe optical image in the same direction; a zooming unit operativelycoupled to the zoom optical system to cause the zoom optical system toperform a zooming operation; and a light adjusting mechanism disposedbetween the first lens group and the second lens group, the lightadjusting mechanism being configured to adjust the amount of lightpassing through the zoom optical system, the lens barrel beingconfigured to change between an imaging state and a retracted state, inthe imaging state, the zooming operation being performed where the firstlens group, the second lens group, and the third lens group are alignedwith one another along the optical axis, during the zooming operation,the second lens group moves integrally with the third lens group alongthe optical axis and the light adjusting mechanism and the second lensgroup move independently of each other along the optical axis, and inthe retracted state, the second lens group being disposed off centerfrom the first lens group along the direction perpendicular to theoptical axis.
 2. The lens barrel according to claim 1, wherein duringthe zooming operation, the light adjusting mechanism and the first lensgroup move independently of each other along the optical axis.